001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.coding;
021
022import java.io.File;
023
024import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
025import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
026import com.puppycrawl.tools.checkstyle.api.DetailAST;
027import com.puppycrawl.tools.checkstyle.api.FullIdent;
028import com.puppycrawl.tools.checkstyle.api.TokenTypes;
029
030/**
031 * <div>
032 * Ensures that a class has a package declaration, and (optionally) whether
033 * the package name matches the directory name for the source file.
034 * </div>
035 *
036 * <p>
037 * Rationale: Classes that live in the null package cannot be imported.
038 * Many novice developers are not aware of this.
039 * </p>
040 *
041 * <p>
042 * Packages provide logical namespace to classes and should be stored in
043 * the form of directory levels to provide physical grouping to your classes.
044 * These directories are added to the classpath so that your classes
045 * are visible to JVM when it runs the code.
046 * </p>
047 *
048 * @since 3.2
049 */
050@FileStatefulCheck
051public final class PackageDeclarationCheck extends AbstractCheck {
052
053    /**
054     * A key is pointing to the warning message text in "messages.properties"
055     * file.
056     */
057    public static final String MSG_KEY_MISSING = "missing.package.declaration";
058
059    /**
060     * A key is pointing to the warning message text in "messages.properties"
061     * file.
062     */
063    public static final String MSG_KEY_MISMATCH = "mismatch.package.directory";
064
065    /** Is package defined. */
066    private boolean defined;
067
068    /**
069     * Whether the file is a JEP 512 compact source file, which lives in the
070     * unnamed package by definition and cannot declare a package.
071     */
072    private boolean isCompactSourceFile;
073
074    /**
075     * Whether the file is a modular compilation unit, which consists of a
076     * module declaration and cannot declare a package.
077     */
078    private boolean isModularCompilationUnit;
079
080    /** Control whether to check for directory and package name match. */
081    private boolean matchDirectoryStructure = true;
082
083    /**
084     * Creates a new {@code PackageDeclarationCheck} instance.
085     */
086    public PackageDeclarationCheck() {
087        // no code by default
088    }
089
090    /**
091     * Setter to control whether to check for directory and package name match.
092     *
093     * @param matchDirectoryStructure the new value.
094     * @since 7.6.1
095     */
096    public void setMatchDirectoryStructure(boolean matchDirectoryStructure) {
097        this.matchDirectoryStructure = matchDirectoryStructure;
098    }
099
100    @Override
101    public int[] getDefaultTokens() {
102        return getRequiredTokens();
103    }
104
105    @Override
106    public int[] getRequiredTokens() {
107        return new int[] {TokenTypes.PACKAGE_DEF};
108    }
109
110    @Override
111    public int[] getAcceptableTokens() {
112        return getRequiredTokens();
113    }
114
115    @Override
116    public void beginTree(DetailAST ast) {
117        defined = false;
118        isCompactSourceFile = ast != null
119                && ast.getType() == TokenTypes.COMPACT_COMPILATION_UNIT;
120        isModularCompilationUnit = ast != null
121                && ast.findFirstToken(TokenTypes.MODULE_DEF) != null;
122    }
123
124    @Override
125    public void finishTree(DetailAST ast) {
126        if (!defined && !isCompactSourceFile && !isModularCompilationUnit && ast != null) {
127            log(ast, MSG_KEY_MISSING);
128        }
129    }
130
131    @Override
132    public void visitToken(DetailAST ast) {
133        defined = true;
134
135        if (matchDirectoryStructure) {
136            final DetailAST packageNameAst = ast.getLastChild().getPreviousSibling();
137            final FullIdent fullIdent = FullIdent.createFullIdent(packageNameAst);
138            final String packageName = fullIdent.getText().replace('.', File.separatorChar);
139
140            final String directoryName = getDirectoryName();
141
142            if (!directoryName.endsWith(packageName)) {
143                log(ast, MSG_KEY_MISMATCH, packageName);
144            }
145        }
146    }
147
148    /**
149     * Returns the directory name this file is in.
150     *
151     * @return Directory name.
152     */
153    private String getDirectoryName() {
154        final String fileName = getFilePath();
155        final int lastSeparatorPos = fileName.lastIndexOf(File.separatorChar);
156        return fileName.substring(0, lastSeparatorPos);
157    }
158
159}